diff --git a/reid/src/mir/typecheck.rs b/reid/src/mir/typecheck.rs
index 93edf9f..b2c97cc 100644
--- a/reid/src/mir/typecheck.rs
+++ b/reid/src/mir/typecheck.rs
@@ -503,13 +503,17 @@ impl Expression {
                 Ok((_, ty)) => Ok(ty),
                 Err(e) => Err(e),
             },
-            ExprKind::Indexed(expression, elem_ty, _) => {
+            ExprKind::Indexed(expression, elem_ty, idx_expr) => {
                 // Try to unwrap hint type from array if possible
                 let hint_t = hint_t.map(|t| match t {
                     TypeKind::Array(type_kind, _) => &type_kind,
                     _ => t,
                 });
 
+                // Typecheck and narrow index-expression
+                let idx_expr_res = idx_expr.typecheck(state, typerefs, Some(&TypeKind::U32));
+                state.ok(idx_expr_res, idx_expr.1);
+
                 // TODO it could be possible to check length against constants..
 
                 let expr_t = expression.typecheck(state, typerefs, hint_t)?;
diff --git a/reid/src/mir/typeinference.rs b/reid/src/mir/typeinference.rs
index dd06051..7192def 100644
--- a/reid/src/mir/typeinference.rs
+++ b/reid/src/mir/typeinference.rs
@@ -105,6 +105,7 @@ impl Block {
                         (var_ref.as_mut(), expr_ty_ref.as_mut())
                     {
                         var_ref.narrow(&expr_ty_ref);
+                        dbg!(var_ref);
                     }
                 }
                 StmtKind::Set(lhs, rhs) => {
@@ -252,9 +253,13 @@ impl Expression {
                     ReturnKind::Soft => Ok(block_ref.1),
                 }
             }
-            ExprKind::Indexed(expression, index_ty, _) => {
+            ExprKind::Indexed(expression, index_ty, idx_expr) => {
                 let expr_ty = expression.infer_types(state, type_refs)?;
 
+                // Infer and narrow types used for indexing
+                let mut idx_ty = idx_expr.infer_types(state, type_refs)?;
+                idx_ty.narrow(&type_refs.from_type(&U32).unwrap());
+
                 // Check that the resolved type is at least an array, no
                 // need for further resolution.
                 let kind = expr_ty.resolve_weak().unwrap();
diff --git a/reid_src/array.reid b/reid_src/array.reid
index f25f0a6..1062f7f 100644
--- a/reid_src/array.reid
+++ b/reid_src/array.reid
@@ -1,13 +1,13 @@
 // Arithmetic, function calls and imports!
 
-fn array() -> [[[u16; 4]; 1]; 1] {
-    return [[[10, 15, 7, 9]]];
+fn array() -> [u16; 4] {
+    return [10, 15, 7, 9];
 }
 
 fn main() -> u16 {
     let mut list = array();
 
-    list[0][0][3] = 5;
+    let a = 1;
 
-    return list[0][0][3];
+    return list[a + 1];
 }
diff --git a/reid_src/array_structs.reid b/reid_src/array_structs.reid
index 179c7fa..89c001b 100644
--- a/reid_src/array_structs.reid
+++ b/reid_src/array_structs.reid
@@ -11,7 +11,10 @@ fn main() -> u32 {
         second: [6, 3, 17, 8],
     }];
 
-    value[0].second[2] = 99;
+    let val1 = 0;
+    let val2 = 1;
+
+    value[val1].second[val2 + 1] = 99;
 
     return value[0].second[2];
 }